Prior to 2005, Missouri trust law was a mixture of statutes and case law, which was quite difficult to decipher consistently. In 2005, the state enacted its version of the Uniform Trust Code, which codified the requirement for an accounting.
Earlier case law provides that "Four elements are required to establish equitable jurisdiction for a trust accounting: (1) the need for discovery, (2) the complicated nature of the accounts, (3) the existence of a fiduciary or trust relationship, and (4) the inadequacy of legal remedies; of these, the existence of a fiduciary relationship is the most critical element to support the exercise of equitable jurisdiction." Tobias v. Korman, 141 S.W.3d 468 (2004).
The above is arguable, and would require a court to completely resolve -- though I suspect that you would lose the argument, because the beneficiary of the unitrust has an interest in an accounting of its distributions in the main trust.
The secondary issue, however, is whether or not the law, as modified, controls the earlier trust. There is nothing in the trust instrument itself to suggest that the law was frozen in 1994. The trust language merely provides that Missouri law shall control. This means that absent impairment of a vested interest under the constitutional "obligations of contracts
" clause, there is no reason to think that you would not have a duty to account, based upon current Missouri law.
This is not a circumstance where the law cuts off a beneficiary's right to income or assets from the trust. It's a procedural change in law which reasonably requires that an accounting occur each year.
BotXXXXX XXXXXne, I don't think you can avoid this accounting, other than to just ignore the request and see what happens. If I were the judge, I would order you to account.
Hope this helps.